infopanel: Add choice of date display formats

Summary:
Let user choose date display format via checkbox in context menu

Example

Depends on D11242

FEATURE: 392352

Test Plan: visual inspection

Reviewers: Dolphin, markg, ngraham

Reviewed By: markg, ngraham

Subscribers: broulik, markg, ngraham

Tags: Dolphin, KDE Applications

Differential Revision: https://phabricator.kde.org/D11245